Chromatographic separating apparatus and method

ABSTRACT

A chromatographic separating apparatus and method has at least a first chromatographic column having a separating material therein, having a length and is positioned in a first temperature zone maintained at a temperature (T1) and a second chromatographic column, serially connected with the first column, having the separating material therein having a length and is positioned in a second temperature zone maintained at a temperature (T2) which is of a different value than the first temperature (T1). Means are provided for passing sample fluid into the first column. The column is adapted to separate at least one preselected component from the fluid sample which comprises a multiplicity of components.

Ayers et'al.

[ Feb. 11, 1975 CHROMATOGRAPHIC SEPARATING APPARATUS AND METHOD Assignee:

Filed:

Appl. No.: 254,742

Inventors: Buell 0. Ayers; Raymond D.

McCoy, both of Bartlesville, Okla.

Phillips Petroleum Company, Bartlesville, Okla.

May 18, 1972 References Cited UNITED STATES PATENTS Burow 55/67 Dawson, .lr,. 55/67 X Wilhelm 55/67 X Haruki et al 55/67 2ND COLUMN SYSTEM Primary Examiner-John Adee Attorney, Agent, or Firm-Quigg & Oberlin [57] ABSTRACT A chromatographic separating apparatus and method has at least a first chromatographic column having a separating material therein, having a length and is positioned in a first temperature zone maintained at a temperature (T and a second chromatographic column, serially connected with the first column, having the separating material therein having a length and is positioned in a second temperature zone maintained at a temperature (T which is of a different value than the first temperature (T Means are provided for passing sample fluid into the first column. The column is adapted to separate at least one preselected component from the fluid sample which comprises a multiplicity of components.

10 Claims, 1 Drawing Figure 1ST COLUMN SYSTEM SAMPLE GASQ |-22 CHROMATOGRAPHIC SEPARATING APPARATUS AND METHOD it is desirable to provide a chromatographic separating system and method which have greater flexibility of component separation for subsequent component analysis of a hydrocarbon sample fluid.

in summary, this invention therefore resides in a chromatographic separating apparatus and method having at least a first chromatographic column having a separating material therein, having a length, and being positioned in a first temperature zone maintained at a temperature T, and a second chromatographic column, serially connected with the first column, having the separating material therein, having a length, and being positioned in a second temperature zone maintained at a temperature T which is of a different value than the first temperature T Means are provided for passing sample fluid into the first column. The column is adapted to separate at least one preselected component from the fluid sample which comprises a multiplicity of components. in addition, the lengths of at least the first and second columns can be varied to provide a system which would provide the separation that could be obtained through a single column operated at an infinite number of temperatures.

Other aspects, objects, and advantages of the present invention will become apparent from a study of the disclosure, the appended claims, and the drawing.

Referring to the drawing, which is a schematic representation of an analytical system embodying the present invention, the analyzing system of this invention has first and second ovens or temperature zones 2, 4. These temperature zones are maintained at different temperatures one from the other. A plurality offirst and second serially connected chromatographic separating columns 6 and 8 are positioned in respective temperature zones 2, 4 thereby establishing a first column system.

The second column system has only a single third column 10, is ofa first length and is positioned in only the first temperature zone 2. A third column system has only a single fourth column 12, a length and is positioned in only the second temperature zone 4.

Other column systems such as the fourth column system can be provided for making other separations and simulating a single column at other temperatures as will be more fully described hereafter. These other column systems, as shown in the drawing, will have two serially connected columns l4, 16 with each column positioned in a separate one of the temperature zones 2, 4, and the length of each column will be different than the length of the respective columns of other column systems.

All of the serially connected columns of the apparatus of this invention have a common separating mate rial 18 therein. The type of material 18 is dependent upon the type of sample fluid being analyzed and can be easily selected by one skilled in the art after this variable is known. Examples of various chromatographic separating materials used in a chromatographic analysis are: squalane, silicone oil, polyethylene glycol and many other high molecular weight organic compounds on a solid support.

Means, such as carrier gas header 20, is provided for selectively passing carrier gas into the upstream column of each column system. Means, such as a sample fluid header 22, is provided for separately passing sample fluid into the most upstream of each column system. A separate chromatographic detector 24, as known in the art, is preferably connected to a discharge end of each of said column systems for separately analyzing materials discharging from each column system.

The temperatures of the first and second temperature zones 2, 4 are preferably maintained at different temperatures whereby one of the temperature zones has a temperature at least two times the temperature of the other temperature zone. By so providing temperature zones that have such relatively different temperatures, the apparatus is adapted to effectively separate and analyze a wider range of gas components. At temperature differences less than about 2X, the analyzing potential of the apparatus decreases. Examples of the temperatures of the first and second temperature zones 2, 4 that have been found to be effective in the analysis of gasoline range hydrocarbons are as follows:

First Temperature Zone Second Temperature Zone A. C. 30C. B. C. 25C. C. C. 50C.

Examples of the capillary column lengths of the system that have been found to be particularly effective in the analysis of gasoline range samples are as follows:

With packed columns, typical column lengths have been found to be:

Column First Column Length Second Column Length System (ft.) (ft.)

First l5 10 Second 25 Third 25 As known in the art, sample is propelled into the column by carrier gas. The controls or valves 26 for so sequentially passing the gases are not a part of this invention and are old in the art. The headers 20, 22 are diagrammatically connected to mixing valves 26 in the drawing without showing the controls in order to more simply set forth the apparatus.

In the method of this invention, a hydrocarbon sample fluid is injected into the column followed by a carrier gas such as helium or hydrogen, for example, to form a resultant mixture.

The sample is passed into the first chromatographic column 6 which is maintained at a temperature T in the first column 6, a first group of components com prising a preselected component of the hydrocarbon sample fluid is separated and passed from the first column 6 to the second column. in the second column 8, at least the preselected component is separated from the first group of components and discharged from the second chromatographic column 8.

In the first column system, the preselected component that is separated is a component having separating temperature,characteristics that are intermediate'the separating temperature characteristics of othercomponents of the hydrocarbon sample fluid.

As known in the art of chromatographicanalysis, constituents of the sample fluid (also called solutes) are separated in time from each other through successive solution and elution from the separating material on each column and are discharged from the columns at different orders or intervals for analysis.

For two serially connected chromatographic columns (for example columns 6, 8), the total carrier :gas -residence time t isequal to the sum of the residence times of the two columns I, t 1 The retention time for any sample component t, is also equal to the sum of the retention times of the two columns t t +1 Another parameter related to retention time known as the solute capacity'ratio is defined ,as k t, t,,/t,,. Hence, for any columnt, (l +.k,)t,, where k, is thecapacity ratio for the sample component i on the given column at a given temperature. The above equations can be combined and rearranged as follows:

Using this equation, the capacity ratios forany two serially connected columns can then be plotted as follows:

Where 11/ r is equal to 0, the values of k, are for column 2 above. When t /t are equal to L0, the values of k, are for column ,1 above.

It has been found that by determining the solute capacity through one column of a known length at two different temperatures T, and T the lengths of serially connected columns operated at T, and T respectively may be varied to simulate a third temperature between T, and T and obtain the solute capacity of the mixture .above, solute capacity ratios can be controlled for maintaining a value substantially equal to'the corresponding solute capacity of the mixture passing through a single column. at a preselected temperature which is between the temperature of the first temperature and the temperature of the second temperature zone.

.By the apparatus and method of this invention, the

equivalent of any temperature between T, and T, can therefore be obtained while actually utilizing only two .l5,

temperature zones, thereby reducing the amount of equipment normally necessary to perform an analysis of a sample requiring a multi-column, multitemperature zone analyzer.

Other modifications and alterations of this invention will become apparent to those skilled in the art from the foregoing discussion and accompanying drawing, and it should be understood that this invention is not to "be unduly limited thereto.

-What is claimed is: l. A methodfor chromatographically separating preselected components from sample fluid having a multi- .plicity of components, comprising:

,passing a portion of said sample fluid into a first chromatographic column having a first length and having a separating material therein maintained at a 'firsttemperature (-T separating in said first column a first group of components comprising a preselected component from theremainder of said portion of said sample fluid;

:passing the thus separated first group of components from said first chromatographic column into a second .chromatographic column having a second length and a separating material therein maintained at a second temperature (T said separating material in said second column being the same as said separating material in said first column, said temperature T being of a value in Centigrade units of at least two times the value of temperature T and the first and second column lengths being adapted to .discharge the preselected, separated component from the second column in an order equivalent to that order of discharge obtained by passing a like sample through a single chromatographic column having the same separating material maintained at a preselected temperature intermediate to the temperatures of the first and second columns;

separating in said second column at least the preselected component from the remainder of said first .group of components; and

discharging the thus separated, preselected component from the second chromatographic column.

2. A method, as set forth in claim 1, wherein the separating temperature characteristics of the preselected component is intermediate the separating temperature characteristics of other components of the sample fluid.

3. A method, as set forth in claim 1, including passing a second portion of said sample fluid into a third chromatographic column having a length and a separating material therein, the separating material in said third column being maintained at said first temperature; and

separating in said third column a group of components from the remainder of said second portion of sample fluid.

4. A method, as set forth in claim 3, including passing a third portion of said sample fluid into a fourth chromatographic column having a length and a separating material therein, the separating material in said fourth column being maintained at said second temperature; and

separating in said fourth column a group of components from the remainder of said third portion of said sample fluid.

5. A method, as set forth in claim 1, including passing a second portion of said sample fluid into a third chromatographic column having a length and a separating material therein, the separating material in said third column being maintained at said second temperature; and

separating in said third column a group of components from the remainder of said second portion of said sample fluid. 6. A method for chromatographically separating preselected components from sample fluid having a multiplicity of components, in at least three chromatographic column systems utilizing only two controlled temperature zones, to achieve the results which would be achieved by operating each of the at least three column systems at its respective temperature, which comprises:

passing a first portion of said sample fluid into a first chromatographic column located within a first controlled temperature zone, said first column having a separating material therein,

separating in said first column a first group of compo nents comprising at least one preselected component from the remainder of said first portion of said sample fluid, passing the thus separated first group of components from said first column into a second chromatographic column located within a second controlled temperature zone, said second column having a separating material therein which is the same as said separating material in said first column,

separating in said second column at least said at least one preselected component from the remainder of said first group of components,

discharging the thus separated, preselected component from said second column and detecting the thus discharged preselected component; passing a second portion of said sample fluid into a third chromatographic column located within said first controlled temperature zone, said third column having a separating material therein,

separating in said third column at least one preselected component from the remainder of said second portion of said sample fluid,

discharging the thus separated, preselected component from said third column and detecting the thus discharged preselected component;

passing a third portion of said sample fluid into a fourth chromatographic column located within said second controlled temperature zone, said fourth column having a separating material therein,

separating in said fourth column at least one preselected component from the remainder of said third portion of said sample fluid,

discharging the thus separated, preselected component from said fourth column and detecting the thus discharged preselected component;

maintaining the columns in said first controlled temperature zone at a first temperature. and

maintaining the columns in said second controlled temperature zone at a second temperature different from said first temperature, the lengths of said first and second columns being such as to provide a solute capacity for said sample fluid equivalent to the solute capacity of a single column employing the same separating material and operated at a third temperature intermediate said first and second temperatures.

7. A method in accordance with claim 6 further comprising:

passing a fourth portion of said sample fluid into a fifth chromatographic column located within said first controlled temperature zone, said fifth column having a separating material therein,

separating in said fifth column a second group of components comprising at least one preselected component from the remainder of said fourth portion of said sample fluid, passing the thus separated second group of components from said fifth column into a sixth chromatographic column located within said second controlled temperature zone, said sixth column having a separating material therein which is the same as said separating material in said fifth column,

separating in said sixth column at least the respective at least one preselected component from the remainder of said second group of components,

discharging the thus separated, preselected component from said sixth column and detecting the thus discharged preselected component;

the lengths of said fifth and sixth columns being such as to provide a solute capacity for said sample fluid equivalent to the solute capacity of a single column employing the same separating material and operated at a fourth temperature intermediate said first and second temperatures.

8. A method in accordance with claim 6 wherein said first temperature is greater than said second temperature.

9. A method in accordance with claim 8 wherein said sample fluid is a hydrocarbon sample fluid.

10. A method in accordance with claim 9 wherein one of said first and second temperatures is at least twice the other of said first and second temperatures in centigrade degrees. 

1. A METHOD FOR CHROMATOGRAPHICALLY SEPARATING PRESELECTED COMPONENTS FROM SAMPLE FLUID HAVING A MULTIPLICITY OF COMPONENTS, COMPRISING: PASSING A PORTION OF SAID SAMPLE FLUID INTO A FIRST CHROMATOGRAPHIC COLUMN HAVING A FIRST LENGTH AND HAVING A SEPARATING MATERIAL THEREIN MAINTAINED AT A FIRST TEMPERATURE (T1), SEPARATING IN SAID FIRST COLUMN A FRIST GROUP OF COMPONENTS COMPRISING A PRESELECTED COMPONENT FROM THE REMAINDER OF SAID PORTION OF SAID SAMPLE FLUID, PASSING THE THUS SEPARATED FIRST GROUP OF COMPONENTS FROM SAID FIRST CHROMATOGRAPHIC COLUMN INTO A SECOND CHROMATOGRAPHIC COLUMN HAVING A SECOND LENGTH AND A SEPARATING MATERIALS THERIN MAINTAINED AT A SECOND TEMPERATURE (T2), SAID SEPARATING MATERIAL IN SAID SECOND COLUMN BEING THE SAME AS SAID SEPARATING MATERIAL IN SAID FIRST COLUMN, SAID TEMPERATURE T1 BEING OF A VALUE IN CENTIGRADE UNITS OF AT LEAST TWO TIMES THE VALUE OF TEMPERATURE T2 AND THE FIRST AND SECOND COLUMN LENGHTS BEING ADAPTED
 1. A method for chromatographically separating preselected components from sample fluid having a multiplicity of components, comprising: passing a portion of said sample fluid into a first chromatographic column having a first length and having a separating material therein maintained at a first temperature (T1); separating in said first column a first group of components comprising a preselected component from the remainder of said portion of said sample fluid; passing the thus separated first group of components from said first chromatographic column into a second chromatographic column having a second length and a separating material therein maintained at a second temperature (T2), said separating material in said second column being the same as said separating material in said first column, said temperature T1 being of a value in centigrade units of at least two times the value of temperature T2 and the first and second column lengths being adapted to discharge the preselected, separated component from the second column in an order equivalent to that order of discharge obtained by passing a like sample through a single chromatographic column Having the same separating material maintained at a preselected temperature intermediate to the temperatures of the first and second columns; separating in said second column at least the preselected component from the remainder of said first group of components; and discharging the thus separated, preselected component from the second chromatographic column.
 2. A method, as set forth in claim 1, wherein the separating temperature characteristics of the preselected component is intermediate the separating temperature characteristics of other components of the sample fluid.
 3. A method, as set forth in claim 1, including passing a second portion of said sample fluid into a third chromatographic column having a length and a separating material therein, the separating material in said third column being maintained at said first temperature; and separating in said third column a group of components from the remainder of said second portion of sample fluid.
 4. A method, as set forth in claim 3, including passing a third portion of said sample fluid into a fourth chromatographic column having a length and a separating material therein, the separating material in said fourth column being maintained at said second temperature; and separating in said fourth column a group of components from the remainder of said third portion of said sample fluid.
 5. A method, as set forth in claim 1, including passing a second portion of said sample fluid into a third chromatographic column having a length and a separating material therein, the separating material in said third column being maintained at said second temperature; and separating in said third column a group of components from the remainder of said second portion of said sample fluid.
 6. A method for chromatographically separating preselected components from sample fluid having a multiplicity of components, in at least three chromatographic column systems utilizing only two controlled temperature zones, to achieve the results which would be achieved by operating each of the at least three column systems at its respective temperature, which comprises: passing a first portion of said sample fluid into a first chromatographic column located within a first controlled temperature zone, said first column having a separating material therein, separating in said first column a first group of components comprising at least one preselected component from the remainder of said first portion of said sample fluid, passing the thus separated first group of components from said first column into a second chromatographic column located within a second controlled temperature zone, said second column having a separating material therein which is the same as said separating material in said first column, separating in said second column at least said at least one preselected component from the remainder of said first group of components, discharging the thus separated, preselected component from said second column and detecting the thus discharged preselected component; passing a second portion of said sample fluid into a third chromatographic column located within said first controlled temperature zone, said third column having a separating material therein, separating in said third column at least one preselected component from the remainder of said second portion of said sample fluid, discharging the thus separated, preselected component from said third column and detecting the thus discharged preselected component; passing a third portion of said sample fluid into a fourth chromatographic column located within said second controlled temperature zone, said fourth column having a separating material therein, separating in said fourth column at least one preselected component from the remainder of said third portion of said sample fluid, discharging the thus separated, preselected component from said fourth column and detecting the thus discharged preselected coMponent; maintaining the columns in said first controlled temperature zone at a first temperature, and maintaining the columns in said second controlled temperature zone at a second temperature different from said first temperature, the lengths of said first and second columns being such as to provide a solute capacity for said sample fluid equivalent to the solute capacity of a single column employing the same separating material and operated at a third temperature intermediate said first and second temperatures.
 7. A method in accordance with claim 6 further comprising: passing a fourth portion of said sample fluid into a fifth chromatographic column located within said first controlled temperature zone, said fifth column having a separating material therein, separating in said fifth column a second group of components comprising at least one preselected component from the remainder of said fourth portion of said sample fluid, passing the thus separated second group of components from said fifth column into a sixth chromatographic column located within said second controlled temperature zone, said sixth column having a separating material therein which is the same as said separating material in said fifth column, separating in said sixth column at least the respective at least one preselected component from the remainder of said second group of components, discharging the thus separated, preselected component from said sixth column and detecting the thus discharged preselected component; the lengths of said fifth and sixth columns being such as to provide a solute capacity for said sample fluid equivalent to the solute capacity of a single column employing the same separating material and operated at a fourth temperature intermediate said first and second temperatures.
 8. A method in accordance with claim 6 wherein said first temperature is greater than said second temperature.
 9. A method in accordance with claim 8 wherein said sample fluid is a hydrocarbon sample fluid.
 10. A method in accordance with claim 9 wherein one of said first and second temperatures is at least twice the other of said first and second temperatures in centigrade degrees. 